"Making is a higher form of thinking," claims Gregor Schneider, who began to make art as an adolescent. So urgent was his desire to be an artist that, in order to pay for the materials he needed to make his sculptures, he even worked as a gravedigger. Introverted, self-effacing and a close observer of human behavior--with a particular passion for the lowliest of social categories--Schneider has developed an all-absorbing identification with his work,...